Once among the brightest of several young Mexican stars, Nery Castillo has fallen out of favor with both Mexico and Chicago, which signed him last year as a Designated Player. FC Dallas has since put its faith, and its money, in Fabian Castillo as a DP, and this week the Fire declined an option on its Castillo.

He fell from grace so fast and so far, it’s hard to comprehend the heights many had predicted for Mexican attacker Nery Castillo just a few years ago, and comparing his arc to that of recent FC Dallas signing Fabian Castillo demonstrates fully the folly of signing the wrong player at the wrong price at the wrong time.

A standout for Mexico in 2007 at the Concacaf Gold Cup and Copa America, Nery Castillo – at the time 23 -- then signed with Ukrainian club Shakhtar Donetsk from Greek club Olympiakos, for which he’d scored 30 goals since arriving in Greece in 2000. The future for the native of San Luis Potosi looked bright if not limited, but even a late bloomer can wither unexpectedly.

Instead, he embarked on a downward spiral of loans to Manchester City (10 games), then back to Ukraine with Dnipro Dnipropetrovsk (three games) last August. Passed over by Mexican coach Javier Aquirre for the 2010 World Cup, he signed on loan with Chicago for an annual salary just over $2 million.

Instead of a springboard to reviving his pro career, Nery Castillo leaves the league as one of the league’s all-time DP busts. MLS loaned him to Greek club Aris in January on a five-month deal with an option to take him back, which the Fire will not do. In eight MLS games, he registered zero goals and zero assists and seldom looked the same player who lit up the Americas four years ago.

In announcing the decision to decline the option, Fire technical director Frank Klopas said, “He didn’t fit in.” That can be applied literally as well as figuratively, as Castillo’s fitness – along with focus, team spirit, and determination – were found lacking.

Contrast his tale to that of Fabian Castillo, an 18-year-old Colombian striker signed from Deportivo Cali in March. The flow of successful Colombian players to MLS, which had nearly dried up five or six years ago, has been restored since the arrival of Juan Toja in Dallas, which sold him to Romanian club FC Steaua Bucharest three years ago after he scored eight goals in 43 matches and made the All-Star team in 2007 and 2008.

In the cockeyed financial muddle that is MLS, Castillo’s compensation is listed at $42,000, so he’s not only the youngest (18) Designated Player in league history, he’s also the lowest paid, at least on paper in 2011. Since league rules mandate that if a player’s total acquisition costs, including salary and transfer fees, exceed $500,000 per season, it can be assumed his salary will skyrocket in the future, and/or the league paid a hefty sum – one source said it was “about” $750,000 – to get him. That’s more than the annual compensation paid to David Ferreira, who after winning the 2010 MVP award was “upgraded” to DP status and is due $705,000 this year.

In nine MLS games, Fabian Castillo has scored twice, and knifed open opposing defenses numerous times. He seems poised enough to adapt on and off the field. Despite being five years younger when he came to MLS, Fabian Castillo carries none of the personality flaws that plagued Nery Castillo after his arrival.

At that same Gold Cup, in the final a young American named Benny Feilhaber scored a spectacular goal that seemed to be a harbinger of great things. Instead, he struggled to find the right club fit for more than three years before joining New England last month. Feilhaber may have finally found the right spot in time to harness the incredible potential that he’s shown glimpses of with the national team.

There’s a danger to players who take too seriously all the wonderful things written and said about them, and no clearer case can be made than Nery Castillo. It may be better to gamble on a younger player eager to establish himself, rather than one who believes a glowing reputation assures success.